[boost] regex doesn't recognize {0} as expected

From: John Maddock (John_Maddock_at_[hidden])
Date: 2001-09-25 06:50:20

>I want to use {0} as a "doesn't match" qualifier, so that
>
>    "abcdef" does not match "^(?:abc){0}"
>
>but, alas, it *does* match.  In fact, it doesn't matter whether I supply
{0} or {1} in the above regex.
>
>How do I express a negative assertion on a multi-character subexpression?

There are currently no lookahead assertions in the regex lib (it is on my
todo list however), the expression you tried doesn't work because "x{0}"
means "repeat x exactly zero times" which is the same as "".

- John Maddock
http://ourworld.compuserve.com/homepages/john_maddock/